In recent years, non-woven fabrics are used widely for various kinds of uses because of having excellent permeability and flexibility. On this account, non-woven fabrics are required to have various properties according to their uses and the properties are required to be further improved.
For example, non-woven fabrics used for sanitary materials such as paper diapers, sanitary napkins and the like, and base fabric such as wet compress pack materials and the like are required to have water resistance and excellent moisture permeability. Furthermore, the non-woven fabrics are required to have stretchability and bulk properties according to a portion for use.
Examples of a method of adding stretchability to the non-woven fabrics are a method of using a thermoplastic elastomer as a material for a spunbonded non-woven fabric (referred to Patent document 1), a method of using mixed fibers which comprise fibers made of a polymer containing a thermoplastic polyurethane elastomer and fibers made of a thermoplastic polymer other than the thermoplastic polyurethane elastomer as fibers for forming a non-woven fabric (referred to Patent document 2). Moreover, differing to the addition of stretchability, a long fiber non-woven fabric obtainable by combining adhesive fibers made of a hydrogenated styrene block copolymer and non-adhesive fibers and the like are variously proposed (referred to Patent document 3).
Mixing the fibers made of the thermoplastic polyurethane elastomer, stretchability is added. Moreover, stretchability (elastic recovery properties) is desired according to the use. As a method of increasing stretchability, there is a method of using a thermoplastic polyurethane elastomer having a low hardness and excellent elastic recovery properties.
However, a thermoplastic polyurethane elastomer having a low hardness is soft. In producing a spunbonded non-woven fabric by mixing fibers made of a thermoplastic polyurethane elastomer having a low hardness, the fibers prepared just after deposition are easily deformed by a rotational device that a linear pressure is applied on the deposited fibers such as calendar roller (for example, referred to Patent document 4), or a conveyer, and thereby the contact area is increased. In the case that fusion bonding of the fibers is insufficient, there is a possibility that the fibers adhere to the rotational device and the insufficient fusion bonding has an industrial problem.
For example, in a process that a web which comprises only long fibers made of a thermoplastic polyurethane elastomer, prepared by a spun bonding method are fusion bonded each other completely or no completely and unified in the step of contacting the web with a rotational device, since a force of generating a peeling force higher than an adhesion force functions in a mechanical direction, fusion bonding is hard to be caused. In the case of producing a spunbonded non-woven fabric which comprises long fibers made of a thermoplastic polyurethane elastomer and long fibers made of a thermoplastic polymer other than the thermoplastic polyurethane elastomer, the fibers are hardly fusion bonded each other in the step of collecting the fibers on a conveyor after opening, and heterogeneous fibers are only deposited and the web is not unified. When the web is contacted with a rotational device such as a calendar roller and the like, the long fibers made of a thermoplastic polyurethane elastomer are adhered on the rotational device at the beginning and the whole web is frequently wound around the rotational device in the end. The production has an industrial problem.
In a process of using mixed fibers which comprise fibers made of a polymer containing a thermoplastic polyurethane elastomer and fibers made of a thermoplastic polymer other than the thermoplastic polyurethane elastomer, a method of coating the roll surface with a silicon resin having a low surface free energy or a material of fluororesin is usually used in order to prevent adhesion of fibers to a roll and the like. The coating is worn away with progressing of the production, and at the time that the surface of a base layer is exposed, the fibers have a possibility of adhesion of the fibers to a roll and the like. The method is not preferred because of having an industrial problem.